Multipoint optical fiber vibrometer

A simple fiber-optic Michelson interferometer for vibration measurement and analysis is presented in this article. It has been conceived and realized with the purpose of using it as the basic measuring element of a complete system for multiple point vibration measurements. One of its main features is that it is operated in the homodyne mode allowing the detection of the direction of motion without using Bragg cells or other optical or mechanical frequency shifting devices, which usually present some inconveniences (alignment problems, dimensions, complexity of the signal processing electronic, and costs). The capability of the fiber interferometer in detecting periodic signals and a comparison with a commercial laser Doppler vibrometer is reported.